Low Molecular Weight Fucoidan Inhibits Pulmonary Fibrosis In Vivo and In Vitro via Antioxidant Activity

Abstract

In this study, sulfated polysaccharides extracted from Laminaria japonica were degraded by free radicals to obtain low molecular weight fucoidan (LMWF). The in vivo and in vitro effects of LMWF on bleomycin-treated pulmonary fibrosis mice and TGF-treated A549 cells, respectively, were evaluated, and the role of antioxidant activity was assessed. H&E, Masson’s trichrome, and Sirius red staining results showed that bleomycin induced obvious pathological changes and collagen deposition in the lung tissue of mice. However, LMWF effectively inhibited collagen deposition, and based on immunohistochemistry analyses, LMWF can also inhibit the expression of fibrosis markers. At the same time, LMWF could regulate related antioxidant factors in the lung tissue of pulmonary fibrosis mice and reduce the pressure of oxidative stress. Moreover, LMWF could improve the morphology of cells induced with TGF, which confirmed that LMWF could inhibit fibrosis via antioxidant activity modulation.

Low–Molecular Weight Fucoidan Polysaccharide Inhibits Pulmonary Fibrosis by Regulating M1/M2 Macrophages Polarization

“…Through experiments, we found that LMWF could reduce the secretion of in ammatory factors (iNOS and TNF-α,) and reduce the expression of in ammation. This shows that LMWF could effectively block the M1 macrophages polarization and inhibit the development of in ammation through its antiin ammatory effect, which is also consistent with our previous experimental research (Dong et al, 2022). Combined with in vitro experimental studies, we con rmed that LMWF could regulate the polarization of M1/M2 macrophages, inhibited the development of in ammation, and blocked the process of brosis.…”

“…However, the speci c mechanism of LMWF on PF is not clear. Although it has been con rmed that LMWF could block the TGF-β/Smad signaling pathway and Nrf-2 to inhibit PF (Wu et al, 2021;Dong et al, 2022), the exact mechanism is still to explore.…”

“…It has shown an inhibitory effect in a PF mice model(Wang et al, 2019;Wu et al, 2021). LMWF can block the ROS to inhibit PF(Dong et al, 2022), but previous studies have not described the mechanism by which LMWF acts on the alveolar macrophage. The purpose of this study was to clarify whether LMWF could act on the alveolar macrophage polarization.…”

“…2.3 Animal experimental samplesAnimal experimental samples were from previous research: male C57BL/6 (8-12 weeks) mice were randomly divided into six groups, with 12 mice in each group: sham (Sham); bleomycin-induced PF; bleomycin-induced PF + low-dose LMWF (25 mg/kg, L-LMWF); bleomycin-induced PF + medium-dose (50 mg/kg, M-LMWF); bleomycin-induced + high-dose LMWF (100 mg/kg, H-LMWF); bleomycin-induced + Nintedanib (NiN)(Dong et al, 2022).…”

Ameliorative Effects of Arctigenin on Pulmonary Fibrosis Induced by Bleomycin via the Antioxidant Activity

“…Bleomycin was injected in all of the groups, except for the Sham group, in which saline was injected instead. The mice received ATG by intraperitoneal injection for 28 days [ 23 , 24 ], whereas the Sham and PF mice were given saline by intraperitoneal injection.…”